1. Field of the Invention
The present invention relates to a device for collecting and burning particulates, such as soot particles, contained in exhaust gases from an internal combustion engine, such as a diesel engine or the like.
2. Description of the Prior Art
Known particulate removal devices include a dust collector which is disposed in an exhaust system of a diesel engine and which comprises, as a main element, a trapper made of porous ceramics, such as a ceramic foam or the like, for collecting particulates therein. Such a particulate removal arrangement will develop an increased pressure loss in the exhaust system and reduce the output power of the engine with an increase in the amount of particulates collected in the trapper. It is therefore necessary to regenerate the trapper at certain intervals of time, for example, each time an automotive vehicle carrying such a trapper travels for several hundred kilometers.
It has been known to regenerate a trapper by burning particulates as attached thereto with an auxiliary burner. However, it is not preferable to install such an auxiliary burner in the exhaust system of an internal combustion engine.
Another known arrangement for regenerating a trapper comprises an electric heater to heat an end surface of the trapper through which an exhaust gas is introduced up to a temperature at which particulates are combustible. Thereafter, secondary air is supplied to burn the heated particulates on the trapper. Generated heat upon combustion is utilized to burn particulates progressively through the trapper to the opposite end surface thereof. The trapper with such electric heater will consume an electric power ranging from 2 to 3 KW until the end surface of the trapper is heated to a temperature (a little higher than 600.degree. C.) at which the particulates are combustible. The trapper is therefore practically infeasible due to a limitation imposed on the maximum electric power available for such trapper.